This invention relates generally to refrigeration equipment and more particularly to chillers for edible food products using cooled liquids to lower the temperature of the food products.
After the processing of edible food products, it is usually necessary to lower the temperature thereof for the purpose of preservation of the product during shipping and storage. This chilling operation is usually required to be performed quickly to prevent spoilage of the products, especially where the processed food product is in an uncooked or partially cooked state, and must also be carried out efficiently, to keep the ultimate cost of the food products economical. Such chilling operations are commonly associated with the poultry processing industry and with the red meat industry, especially sausage products.
This chilling operation is typically carried out by chillers which bring the edible food products into a heat exchange relationship with a cooled heat transfer liquid. These chillers generally have an enclosure through which the food products are moved by a conveyor along a serpentine path. The cooled heat transfer liquid is usually sprayed or otherwise distributed over the top of the enclosure and falls to the bottom of the enclosure by gravity so that the heat transfer liquid comes into a heat transfer relationship with the food products on the conveyor as it falls. The heat transfer liquid is collected at the bottom of the enclosure for recirculation back to the top of the enclosure and is maintained in a cooled condition by appropriate refrigeration equipment. Where such heat transfer fluid comes into direct contact with the edible food product, non-contaminating liquids such as brine solutions are typically used. Where the food products have been packaged in liquid proof packages, other liquids such as propylene glycol are typically used.
One such prior art chiller is illustrated in my earlier U.S. Pat. No. 4,138,860, issued Feb. 13, 1979. This patent has a conveyor which moves the food products along a serpentine path through the enclosure along generally parallel flights at an acute angle to the vertical so that the liquid refrigerant falls onto several of the food products moving along these flights before it reaches the bottom of the enclosure. Another prior art chiller is illustrated in U.S. Pat. No. 3,173,276, issued Mar. 16, 1965, which uses air rather than a liquid as the heat transfer medium. The conveyor in this patent moves along a serpentine path with parallel horizontal flights. Another prior art chiller is illustrated in U.S. Pat. No. 3,315,489, issued Apr. 25, 1967, which uses a plurality of vertically spaced horizontally extending belts to carry the food products and over which the liquid refrigerant is distributed.
These prior art chillers have not been able to maximize the residence time of the food products within the enclosure so as to minimize the amount of floor space required for the chiller while at the same time maximizing the number of food products contacted as the heat transfer liquid falls from the top to the bottom of the enclosure so as to maximize the heat transfer rate out of the food products. As a result, these prior art chillers have not been able to minimize the acquisition and operating costs thereof.